Metal forming process for shaping ends of tubes



Dec. 28, 1965 G. HINDERER 3,

METAL FORMING PROCESS FOR SHAPING ENDS OF TUBES Filed Aug. 21, 1961 2Sheets-Sheet 1 INVENTOR. 60774 05 Jib/0595 z/M M71474 United StatesPatent 3,225,581 METAL FORD LING PROCESS FUR SHAPING ENDS OF TUBESGottlob Hinderer, Sylmar, Calif., assignor to Price-Ffister Brass Mfg.(10., Los Angeles, Calif., a corporation of California Filed Aug. 21,1961, Ser. No. 132,868 6 Claims. (Ci. 72-370) This invention relates tometal forming, and particularly to the forming of the ends of tubes toprovide an inherently reinforced enlarged head or flange for the tube.

Such metal forming may be applied, as in one example, to copper tubingor brass tubing or the like, to provide a curved flange at one end; theflange is used for attaching the tube to a fitting, such as the inletside of a faucet. The tube may be coupled to the inlet, as for a washbasin faucet, to connect the faucet to a shut-off valve located belowthe basin.

It has been common practice to provide a separate reinforcing ring aboutthe enlarged end of the tube, so as to make it possible to strongly urgethe tube end into firm contact with the coupling. Such fabrication ofthe tube is expensive, involved operations being necessary.

It is one of the objects of this invention to make it possible to jointhe tube end so as to provide reinforcement at the end, and this isaccomplished without the addition of reinforcing rings.

It is another object of the invention to make it possible to supply, atlittle cost, a tubular plumbers fitting made of an integral tube andproviding a reinforced head.

In order to accomplish these results, a series of forming tools orpunches is used, operating in succession to provide an enlargement atthe end of the tube, and then reversely to bend the edge of theenlargement to form three layers of metal around the end of the tube.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of oneembodiment of the invention. For this purpose, there is shown a form inthe drawings accompanying and forming a part of the presentspecification, and which drawings, unless described as diagrammatic, orunless as otherwise indicated, are true scale. This form will now bedescribed in detail, illustrating the general principles of theinvention; but it is to be understood that this detailed description isnot to be taken in a limiting sense, since the scope of this inventionis best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a diagrammatic elevation of a press incorporating theinvention;

FIG. 2 is a pictorial view, showing the stages of folding the end of thetube;

FIG. 3 is an enlarged sectional view, showing the manner in which thetube may be attached to a fitting;

FIG. 4 is a View, mainly in section, illustrating the means foraccomplishing the first step in the process of forming the tube, theblank and the punch structure being shown ready for the punchingoperation;

FIG. 5 is a view similar to FIG. 4, but illustrating the completion ofthe first step, and enlarged;

FIG. 6 is a view similar to FIG. 5, but illustrating the completion ofthe second step in which there is a further enlargement formed at theend of the tube;

FIG. 7 is a view similar to FIG. 4, illustrating the completion of thethird or last step; and

FIGS. 7a and 7b are views similar to FIG. 7, illustrating intermediatepositions of the punches.

A tube blank 1 (FIGS. 1, 2(a), and 4) is adapted to be releasablyclamped by the clamping structures 2. This blank is normally made ofquite malleable metal such as copper, to ensure that the bendingoperations will not injure the tube walls.

The blank 1 is a straight tube of uniform diameter, adapted to besupplied to the clamps 2 in any conventional manner. The blank isoperated upon in succession by three punch structures 5, 6, and 7. Thesepunch structures are supported in the present instance in verticalarrangement, upon a common support 8. This support is verticallymoveable so as to align the punch structures 5, 6, and 7, in successionwith the axis of blank 1.

Each of the punch structures at its right-hand end is provided with adisc-like abutment 9, 10, or 11; and is, furthermore, longitudinallymoveable in the support 8.

In the position shown in FIG. 1, the blank 1 is in alignment with thefirst punch structure 5. This structure 5 may be urged toward the leftby a piston 12. This piston 12 can be hydraulically operated by the aidof the cylinder structure 13.

The first operation effected by the aid of punch structure 5 results inan intermediate stage b illustrated by reference character 35 in FIG. 2.This stage now includes an enlarged end 15, joined to the main body oftube 35 by the tapered shoulder 34. The second stage 0 is illustrated byreference character 36 in FIG. 2. In this stage, a further enlargement46 is formed at the end of the tube. Finally, the last stage dcorresponding to the completion of the operation by punch structure 7 isillustrated by tube 14 in FIG. 2. Here the end is reversely bent todefine a spherical zone surface on the exterior.

The punch structures 5, 6, and 7 produce the finished product, shownenlarged in FIG. 3. Here, the completed tube 14 is shown with itsenlarged portion 15. Folded around this enlarged portion are two layersof material formed integrally with the tube 14 and around the outerperiphery forming with the tube three layers in all. These layers 16,17, and 18 are quite closely folded the outer two forming a reinforcedcollar around the exterior of the enlarged part 15.

Furthermore, external layer 18 is curved, preferably as a sphericalzone, which fits a spherical seat 19 of fitting 20. This fitting 20 maycorrespond to the inlet for a valve or the like.

The spherical surface formed on the external layer 18 is urged intoplace by the aid of a conventional nut 21 having an inwardly directedflange 22. This flange engages the loop form between the layers 17 and18, and urges the tube 14 tightly against the seat 19.

The first punch structure 5 is adapted to form the enlargement 15 (FIGS.2, 3, and 5) by expanding the end of the blank 1.

The punch structure 5 as shown in FIGS. 4 and 5, includes the punchholder 23 of generally cylindrical form and integrally formed with thedisc 9. The punch structure carries the punch proper 24, as by the aidof a threaded extremity 24b formed on the shank 24a of the punch 24. Thepunch 24 furthermore has an operating cylindrical portion 25 which isadapted to enter into the blank 1 so as to expand the end of theblank 1. This operating portion 25 is of slightly larger diameter thanthe shank 24a, and it is surrounded at a slight distance therefrom bythe cylindrical walls 27 of a circular recess in the external end of thesleeve member 26. This recess communicates with an adjacent concentricrecess of smaller diameter in the opposite end of the sleeve member,this smaller diameter being substantially the same as that of theaperture 28 which fits the shank 24a. This construction permits thesleeve member 26 to be attached to the shank between the punch holder 23and the end of the tube. The punch proper 25 thus can seat against theshoulder 29 formed between the aperture 28 and the cylindrical surface27.

The outer diameter of the punch proper and the diameter of thecylindrical surface 27 together define an annular space 30 for thereception of the expanded end 15 of the tube.

Extending from the punch proper 25 is a conical or tapered portion 31.When this tapered portion enters the end of blank 1, the expansionbegins. A somewhat narrower tapered portion 32 extends to the left ofthe portion 31 and terminates in a cylindrical piloting end 33.Furthermore, a set screw 64 serves to hold the punch 24 securely inplace in the holder 23.

When the punch structure 5 is in alignment with the blank 1, asillustrated in FIG. 1, the punch structure 5 can be urged toward theleft by the aid of the piston 12. When this force is exerted, thepiloting end 33 snugly enters the end of the blank 1 and continuedpressure applied to the punch structure finally results in the formingof the end of the tube, as illustrated in FIG. 5, to provide theenlarged portion 15, and a tapered portion 34.

The completion of the first operation therefore is illustrated by thetube structure 35 shown in FIG. 2(b).

In order to effect the second operation resulting in the tube structure36 shown in FIG. 2(a), first the support 8 is moved upwardly so as toalign the punch structure 6 with the axis of the tube 35 (FIG. 6). Thepunch holder 37 serves in the same manner to support a punch 38 having acylindrical shank 39. This cylindrical shank terminates in an extension40 threaded into the holder 37 and held securely against removal by setscrew 41.

A flange 42 integral with the punch 38 serves to hold the sleeve 43 inplace against the left-hand end of the holder 37, the sleeve 43 and thecylindrical portion 44 of the punch 38 defining annular space 45corresponding to the still further enlarged extremity 46 of the tube 36.A tapered shoulder 47 extends from the left-hand end of the cylindricalportion 44 and joins reversely tapered portion 48. The tapered portion48 has a taper of one or two degrees, and serves to permit ready removalof the punch after it has completed its operation.

In succession, there are a cylindrical portion 49 corresponding to thediameter of the enlarged portion 15 of the tube 36, a tapered section 50and a piloting end 51 corresponding to the internal diameter of the tube36.

When the structure 6 is brought into alignment with the tube 35 and thepiston 12, as before, force may be exerted to urge the structure towardthe left to produce the configuration of tube 36, shown in FIGS. 2(0)and 6. The annular space between the sleeve 43 and the cylindricalportion 44 corresponds quite closely with the thickness of the tubewall.

After the punch structure 6 is withdrawn, the support 8 is moved onestep upwardly to align the punch structure 7 with the tube 36. Thispunch structure 7, shown in FIG. 7, includes the holder 23 and is heldas by the set screw 34 in a firmly fixed position.

The punch proper 52 includes a shank 53 and an enlarged cylindricalportion 54. This cylindrical portion 54 serves to hold the sleeve 55tightly against the left-hand end of the holder 23. This is accomplishedin the same manner as before.

The sleeve 55 defines at its left-hand end a concave spherical surface56 (see also FIGS. 7a and 7b). This surface is that of a spherical zonehaving a center 57 on the axis of the finished tube 14. The larger endof the zone corresponds to the left-hand end of the sleeve. It has adiameter corresponding to the outer diameter of the enlarged end 46.

The punch 52 has a narrow tapered shoulder 58. The taper of thisshoulder is such that the. cone elements defining this taper arecentered on the center 57.

The punch 52 has in succession a cylindrical portion 59 which is aboutthe same diameter as the internal diameter of the enlarged portion 15.The punch structure also includes the tapered shoulder 60 and a pilotingend 61.

As the sleeve 55 is urged toward the left, as viewed in 4 FIGS. 7, 7a,and 7b, the enlarged end 46 of tube 36 is bent inwardly to define aspherical member 63, which ultimately forms the outermost layer 18 ofFIG. 3. This inward bend is effected by continued contact of the concavezone 56 with the outer periphery of the portion 46.

The conclusion of this part of the folding is illustrated in FIG. 7a.The continued application of the compressive force toward the leftexerted by the punch structure 7 causes a fold to develop shown inincipient form by reference character 62 in FIG. 7a. The bending ring 62is formed at the inner end of the outer enlarged portion 46. Thus thebending ring is formed by the frustoconical part 47 (FIG. 6). The foldthus begun as indicated in FIG. 7a is compressed as shown in FIG. 7b andends with a complete fold as shown in FIG. 7. To ensure that the portion63 will not converge beyond the spherical surface 56, the small end ofthe zone has a stop defined by the tapered shoulder 58. This taperedshoulder thus prevents further inward movement of the metal and ensuresfolding to the ultimate form shown in FIGS. 3 and 7.

The inventor claims:

1. The process of making a plumbing fitting from a malleable tube ofsubstantially uniform cross-section, which comprises: securing the tubeby a clamping device so that a length of the tube is exposed beyond thedevice; driving a forming tool into the end of the tube to define anenlarged end that merges with the main body of the tube at asubstantially conical part to form a bending ring; forcing the edge ofthe enlarged end progressively into a converging recess to provide anexternal surface contour; and applying a longitudinal compressive forcebetween points of the tube spaced on opposite sides of said bending ringto fold material from the enlarged end rearwardly beyond the bendingring at a place spaced from said clamping device.

2. The process of making a plumbing fitting from a malleable tube ofsubstantially uniform cross-section, which comprises: securing the tubeby a clamping device so that a length of the tube is exposed beyond thedevice; driving a forming tool into the end of the tube to define anenlarged end that merges with the main body of the tube at asubstantially conical part to form a bending ring; forcing the edge ofthe enlarged end into the outer area of a converging recess and againsta stop at the inner area of the converging recess, and continuing theapplication of longitudinal force to the tube from a point beyond saidbending ring to fold material from the inner portion of the enlarged endrearwardly beyond said bending ring at a place spaced from said clampingdevice until said material at the area of the bending ring underlies theouter portion of the enlarged end to reinforce the same.

3. The process of forming reinforcing external bands on the end of ametal tube, the outermost band having a substantially spherical surface,said process comprising: securing the tube by a clamping device so thata length of the tube is exposed beyond the device; enlarging the tubefrom the very end thereof to a point inwardly of the end; urging theedge of the tube against the concave surface of an annular abutment thatis curved substantially as a spherical zone and forcing the edgeinwardly of the spherical zone to constrict the edge of the tube and theadjoining portions thereof until the edge of the tube meets an abutmentto define an opening; and continuing the force urging the end againstthe abutment to fold the curved end around the outer surface of the tubethat is exposed beyond said clamping device.

4. The process of enlarging the end portion of a tube and formingreinforcing external bands thereon, which comprises: securing the tubeby a clamping device so that a length of the tube is exposed beyond thedevice; enlarging the end of the tube from the very end thereof to apoint inwardly of the end; forcing the edge of the enlarged end and aprogressively encircling concave abutment together to form asemi-spherical convex end portion; and inserting a pressure resisitingmember into the tube end, while it is traversing said concave abutment,to receive the pressure of said edge and cause the end portion of saidtube to form into a reverse bend externally around the tube at a placespaced from said clamping device.

5. The process of enlarging the end portion of a tube and formingreinforcing external bands thereon, said process including the followingsteps: securing the tube by a clamping device so that a length of thetube is exposed beyond the device; forcing an enlarged mandril into saidtube to form an enlarged portion; and then forcing the edge of theenlarged portion of said tube and a progressively encircling concaveabutment together to constrict said enlarged portion adjacent said edgeand to form it into a semi-spherical convex end portion and continuingthe force until the convex end portion telescopes over the adjoiningportion of the tube that is spaced from said clamping device to formthree overlapping layers.

6. The process of enlarging the end portion of a tube and formingreinforcing external bands thereon, said process including the followingsteps: securing the tube by a clamping device so that a length of thetube is exposed beyond the device; forcing a first enlarging mandrilinto said tube to form an enlarged portion spaced from said clampingdevice and adjacent one end; forcing a second enlarging mandril oflarger diameter than said first mandril partially into said enlargedportion to form a further enlarged segment thereof and a residualenlarged portion adjoining said segment; and then forcing the edge ofthe enlarged outer segment and a progressively encircling concaveabutment together to form the enlarged segment adjacent said edge into asemi-spherical convex end portion and continuing the force until theresidual enlarged portion of the tube telescopes into said said convexend to form three overlapping layers.

References Cited by the Examiner UNITED STATES PATENTS 1,152,858 9/1915Stewart 15321 1,804,814 5/1931 Schultis 153-79 1,817,854 8/1931 Sorensen15379 2,460,110 1/ 1949 Stinchcomb et a1. 285 2,552,768 5/1951 Brophy285122 2,746,325 5/1956 Kjellberg 81--15 2,7 80,122 2/1957 McCown 81-152,857,666 10/1958 Beyer 29541 FOREIGN PATENTS 312,024 5/ 1929 GreatBritain. 709,061 5/1954 Great Britain.

CHARLES W. LANHAM, Primary Examiner.

WH-ITMORE A. WILTZ, NEDWIN G. BERGER,

MICHAEL V. BRINDISI, Examiners.

1. THE PROCESS OF MAKING A PLUMBING FITTING FROM A MALLEABLE TUBE OF SUBSTANTIALLY UNIFORM CROSS-SECTION, WHICH COMPRISES: SECURING THE TUBE BY A CLAMPING DEVICE SO THAT A LENGTH OF THE TUBE IS EXPOSED BEYOND THE DEVICE; DRIVING A FORMING TOOL INTO THE END OF THE TUBE TO DEFINE AN ENLARGED END THAT MERGES WITH THE MAIN BODY OF THE TUBE AT A SUBSTANTIALLY CONICAL PART TO FORM A BENDING RING; FORCING THE EDGE OF THE ENLARGED END PROGRESSIVELY 